when did this happen? How much time have you given him to recuperate. Yes, cham lungs are a lot smaller than ours and a 4 month's old that much smaller. Can you post a pic of him?
For now, my 2 cents is to put him in a glass tank (10-20gal) with padding on the bottom (in case he falls or does not want/can't to climb). Don't use terry towels as his claws can get caught. lots of paper towel will work, in fact you can place that as a covering on some terry towels. Put in some branches so he can cliong and feel secure. Put him in a quiet, low activity area. My reason for the glass tank is to keep him secure and easier to water, feed, keep warm. Use a lower watt basking bulb, as heat will build up in glass. Mist him with a very fine mist (you can buy an small empty plastic or glass spray bottle in the cosmetic section of most drug and discount stores). Use hot water. It will cool a bit when it hits the air. Do NOT force feed or water him. chams do not have a sphincter (close-off) for their esophagus so they can easily aspirate.
Keep him warm, get humidity up a couple times/day but be sure all is dry before lights out (you may need to change the padding in order to do this) so he does not get chilled. Since his lungs and respiratory system are compromised he would be more prone to URI or other complications. See how he is in the morning and offer him a soft bodied feeder - young cricket, waxworm, silkworm).
Where do you live? You might be surprised to find a vet. Tell us city and state and someone may be able to direct you. That said, I would wait to see a vet as it will add stress unless he develops an URI. Look for stringy mucous, wheezing, gaping.
Monitor his temps carefully. Not with strip therm, use a temp gun if you have one (or buy one at tempgun.com for $25).
I am sure there will be other suggestions from more experienced keepers. Please keep us updated on his progress.
I am glad you did not lose your house and that no one else was hurt!
